1. Field of the Invention
The present invention relates to a method for manufacturing an electronic component module, in which an electronic component module including a grounding electrode extending around the bottom thereof is cut from a collective substrate with a plurality of electronic component modules including a plurality of electronic components.
2. Description of the Related Art
Conventionally, when manufacturing an electronic component module, a collective substrate including a variety of electronic components is batch-sealed with a resin, and a groove (cut) section is formed from a top surface of the sealed resin to a position that reaches a grounding electrode, at a boundary section for cutting into electronic component modules. Then, after filling the groove section with a conductive paste, individual electronic component module units are cut from the boundary section, thereby manufacturing electronic component modules (see Japanese Patent Application Laid-Open No. 2004-172176).
However, in the manufacturing method disclosed in Japanese Patent Application Laid-Open No. 2004-172176, unless the groove section is to be filled with a relatively large amount of conductive paste with a relatively small viscosity in order to fill the groove section with the conductive paste, the bottom of the groove section may be incompletely filled or filled with the conductive paste including air bubbles. In this case, as the conductive paste is generally a thermosetting resin, voids will likely occur within the resin layer during curing, leading to a problem in that the electronic components may be insufficiently shielded from electric field noises and electromagnetic wave noises.
Furthermore, in order to avoid the problem mentioned above, a diluted solution of the conductive paste is often used to lower the viscosity of the conductive paste. However, in this case, the diluted solution may be gasified during curing of the thermosetting resin, which results in voids within the resin layer due to gas from the vaporization of the diluted solution. Therefore, the use of the diluted solution does not effectively solve the problem that the electronic components may be insufficiently shielded from electric field noises and electromagnetic wave noises.
Thus, for example, in Japanese Patent Application Laid-Open No. 11-163583, a thin-film shield layer defined by a nickel plating layer or other suitable layer is formed instead of the conductive paste. The nickel plating layer is easily formed into a thin film, which is formed by immersing a base material in a plating solution to induce metal precipitation on the surface. Thus, no air bubbles will be included in the film, unlike the case of the paste application, thereby preventing voids from occurring.
Moreover, Japanese Patent Application Laid-Open No. 2005-79139 discloses a method for forming a shield layer by spray coating. Since the spray coating forms a thin film shield layer, air bubbles are not likely to be included in the shield layer, as in the case of Japanese Patent Application Laid-Open No. 11-163583, thereby preventing voids from occurring.
However, the manufacturing method disclosed in Japanese Patent Application Laid-Open No. 11-163583 requires the immersion of the electronic component package in a plating solution in order to form the shield layer of a nickel plating layer. Therefore, the immersion in the plating solution may cause the plating solution to penetrate into the sealed resin, which may lead to a problem of damage to the electronic components due to the plating solution and decreased reliability due to water absorption by the sealed resin.
Furthermore, in Japanese Patent Application Laid-Open No. 2005-79139, in the case of batch-shielding a plurality of modules, it is difficult to form the shield layer uniformly on side surfaces of the packages unless the groove section between the packages has a sufficiently large width, which leads to a problem that the electronic components may be insufficiently shielded from electric field noises and electromagnetic wave noises. Furthermore, in the case of spray coating, because a highly flammable conductive resin is sprayed, facilities are required to have explosion-proof specifications, which leads to the problem of high production cost.